Electroportable device for placing clinch-on nuts or break-off stem blind rivets

ABSTRACT

Electroportable apparatus for positioning nuts to be set and the setting of blind rivets whose shank ruptures includes a body of the eledtroportable type containing an electric motor, a mandrel, drive part to maintain and pull the head of the rivet and/or to pull, screw or unscrew the nut to be set, as well as a part for pre-regulating the path of the mandrel.

BACKGROUND OF THE INVENTION

The invention concerns an electroportable apparatus for setting nuts orblind rivets whose shanks rupture.

DESCRIPTION OF THE RELATED ART

At present, apparatus for setting nuts or blind rivets whose shanksruptures rupture, are supplied by electrical cables or pneumatic cables.Along assembly lines where several people work, there is rapidly anoverlapping of wires which is undesirable for working safety.

More and more, industries are oriented toward apparatus of this type,which is portable and which imparts comfort and efficiency to work.These portable apparatuses are very bulky and highly energy consumptive.They therefore have a short charge and must often be recharged.

The state of the art can be defined by the following patents.

WO95/13887: The tool for setting rivets and self-tapping screws,comprises a movable body, terminating in a head permitting holding therivet or the self-tapping screws so as to be driven in rotation by theelectrical motor with gearing and by means of the intermediate screwwhich is provided with a pulling device. The tool is contained in ahousing of the electroportable type, and provided with aloader-distributor of screws or self-penetrating rivets.

WO96/25258: The invention relates to a self-piercing riveting device,actuated by a motor and comprising a housing held by an operator. Thehousing contains a motor driving a principal pinion, connected by atransmission wheel to the cam driving a riveting mechanism, this latterbeing well known in the field of art to which it relates. The abovemechanism is installed in an independently rotatable cylinder turningdirectly the riveting mechanism. When the device operates, a rotativecouple is first impressed on the riveting mechanism by the transmissionwheel so as to clamp the jaws about a shank until the rotation couple isminimal, necessary to burst a rivet, namely, superior to that which isrequired to pierce a workpiece to be machined; the transmission wheelwill then cease to turn to transform it into an orbital wheel for thedrive pinion. The rotatable cylinder then causes to turn and move theself-piercing rivet. Boring of the workpiece takes place until the rivetis emplaced. Increased pressure on the trigger switch brakes therotatable cylinder, driving the rotatable coupler rearwardly on thetransmission wheel to shape the rivet, after which the cam, because ofmaintaining the braking pressure controlled by the triggering switch,gives rise to the return by 360° of arc, of the mechanism, so as to getrid of the shank that was used and to receive another.

EP-A-0 670 199: Apparatus for placing the female portion of a blindrivet is provided, with a traction rod, a motor, a first drivetransmission to generate rotatable movement of the traction rod andwhich can be interrupted and a second drive transmission which has adrive portion and a driven portion and in which the driving portion canbe moved over a path of movement and which has an empty space relativeto the driven portion and a usable path.

FR-A-2.706.338: The invention relates to a riveting tool with a systemfor sucking up rivets, comprising a body which is connected to a lowerportion and carrying an upper portion with a gripping assembly for theshank of the rivet that is hydraulically controlled, said grippingassembly being provided with a pincers mandril and a hydraulic jackbeing connected to a space above the upper portion of the pneumaticpiston which is formed in the body of the tool, an air outlet under thepressure of a control valve opening into a space below the lower portionof the pneumatic piston which is guided in a cylindrical reinforcementof the lower portion of the tool, said control valve being fixed in animperforate separation wall of the lower portion of the tool and beingconnected by means of a valve rod, freely guided in the longitudinalrecess of the body, with a detent which is slidably mounted in atransverse guide.

There are known devices having less encumbrance. Thus, EP-A-0 527 414provides an apparatus for blind rivets with a housing and a tractiondevice having a gripping mechanism, which can be moved by an electricmotor by means of a drive device. Such an apparatus for blind rivetsmust be actuated with increased comfort. To do this, the drive apparatusas a demultiplying ratio independent of the position of the tractiondevice and giving rise to a permanent relationship between the electricmotor and a traction device which ensures that the movement of thetraction device takes place solely under the control of the electricmotor.

Such an apparatus however does not give entire satisfaction.

First, there is proposed a constant demultiplication ratio all along thepath of the traction device. An important drawback of this choice isthat a maximum drive couple in the middle of the path cannot betargeted, which is to say at the moment at which the riveting requiresthe greatest coupling.

Moreover, the design of the apparatus according to EP-A-0 527 414 isvery particular to the transmission system. The horizontal position ofthe motor is less ergonomic and the choice of a ball screw coaxial withthe traction device to actuate it is a heavy and costly technicalsolution.

Moreover, it is essentially the relaxation of the trigger which controlsthe return of the traction device. This path control is different fromthat of the present invention and has the drawback of risking badriveting if the operator too quickly releases the trigger or if he doesnot detect an anomaly such as wire drawing.

Finally, economy of electrical consumption is not optimal, because itcan be, by tardy release of the trigger, that the traction path that isnecessary and sufficient is exceeded.

SUMMARY OF THE INVENTION

The present invention seeks to overcome the drawbacks of the presentart.

The apparatus according to the invention, for the setting of screws orblind rivets, is of the type comprising an electroportable body,containing an electric motor, a mandrel, drive means to maintain andpull on the nail or rivet and/or to pull, screw or unscrew the nut to beset.

The apparatus further comprises preadjustment means of the path of themandrel, permitting, after the pre-regulated course of the mandrel, anautomatic return.

The invention can take several embodiments disclosed hereafter.

The amplitude of the path of the mandrel is adjustable as a function ofthe size of the nut or rivet to be set.

Adjustment of the path of the mandrel is a distance adjustment.

The pre-adjustment means are constituted by a slider which moves adetector that is movable relative to a fixed detector.

The pre-selection of the rivet and/or of the nut to be set is carriedout by a potentiometer which measures electronically the distance of thepath of the mandrel.

The mechanical apparatus for setting blind rivets comprises an electricmotor driving a ball screw, which drives by means of balls, a toothedwheel actuating a rack driving the riveting mechanism.

The electric motor is a coupled motor.

The drive means actuating the riveting mechanism are actuated by ahydraulic micro-central, the motor actuates the hydraulic micro-central,and energy transmission takes place by means of a hydraulic pump, whichis an integral portion of the hydraulic micro-central.

The mandrel is adapted to position nuts and an electric motor isdisposed on the working axis of the mandrel for screwing or unscrewing.

The trigger of the apparatus is the control means, the first pullactuating screwing of the second pull actuating pulling along apredetermined path with automatic return and upon releasing the trigger,the automatic unscrewing action for x turns of the motor and stoppingsaid motor.

The trigger is connected by a branched distributor to a connectionsocket, itself connected to another socket, which is connected to thehydraulic circuit, which supplies point A and point B and on the otherhand the piston, secured to the hollow mandrel, O-rings ensuring thesealing of the hydraulic assembly, a return spring for the hollowmandrel, the end of the hollow mandrel is disposed at the level of therecess, which gathers the nails when they are pulled, and that the endof the hollow mandrel is located at the level of the nose and of thepulling broach of the electrohydraulic riveter.

The trigger has two functions:

first, the trigger closes in a first instance the hydraulic circuit Aand B,

secondly, the same trigger starts the motor, which drives the pump, forthe regulated pre-established path, and that the release of the triggerby opening the hydraulic circuit, drives the return of the piston,namely of the hollow mandrel to the rear. The electric motor ispositioned substantially along the vertical axis of the electroportablebody and is mounted with a freedom of movement in pivoting relative tothe electroportable body.

The adjustment of the path of the mandrel is a distance adjustment.

The cycle of operation of the electroportable riveter with an adjustablepath can be the following.

The motor-couple is supplied by a power circuit closed by two relayswhich permit the circulation of current and its inversion.

The control circuit is controlled by a sequential command or a holdingcontact. This control is actuated by a control trigger disposed on thebody of the apparatus. The current flows then into a first branch of thecontrol circuit. This first branch is opened by a contact whichsymbolizes the end of path contact. The switch then swings to supply asecond branch of the control circuit which controls a relay, the powercurrent circulates in the reverse direction, the motor-couple changes asto direction of rotation and returns the drive means to the initialposition.

It will thus be understood that the trigger controls the starting of thecycle but that it does not control the return by inversion of themotor-couple. The return takes place without control, by detection whenthe pre-regulated course is achieved.

In this way, bad riveting is avoided because, upon the systematicexecution of a certain path, the anomalies such as wire drawing will bereduced, as well as sliding by wear of a jaw or else an error ofpunching the sheet metal to be riveted.

According to another embodiment, the drive means actuating the rivetingmechanism are actuated by a hydraulic micro-center.

The motor-couple actuates the hydraulic micro-center.

The transmission of energy takes place by means of a hydraulic pump,which is an integral part of the hydraulic micro-center.

In the embodiment in which the apparatus is adapted to set nuts, themandrel is adapted to position these nuts and an electric motor isdisposed along the working axis of the mandrel to screw or unscrew them.

The trigger of the apparatus is the control means.

The first pull actuates screwing, and, the screwing terminated, pullingcontinues to actuate the traction on the predetermined path with anautomatic return.

Upon releasing the trigger, there is an automatic unscrewing action forx turns of the motor and stopping of said motor.

In the case of low battery, a second pull gives rise to a return to zeroposition.

Preferred embodiments of the invention are given hereafter.

The adjustment of the path of the mandrel is a distance adjustment.There are thus detected the extreme positions of the mandrel for biasingdetectors. Other adjustment means, such as counting the number of turnsof the motor or from the angular position of the toothed drive wheel,can be provided.

The adjustment of the path of the rivet whose dimensions have beenselected, takes place automatically by an electronic control means.

The pre-selection of the rivet and/or of the nut to be set, is carriedout manually by a cursor which moves a movable detector relative to afixed detector.

The pre-selection of the rivet and/or of the nut to be set is carriedout by a potentiometer which controls electrically the distance of thepath of the mandrel.

The characteristic techniques of the motor-couple are to develop maximumpower for several seconds.

The characteristics can be as follows:

couple constant: 19.4 mNm/A

speed constant: 491 tr/min/V

load constant: 8.45 tr/min/mNm

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are given by way of example and notlimitation. They show one embodiment. They permit easy understanding ofthe invention.

FIG. 1 is a schematic view of the apparatus for setting blind rivets,according to an electromechanical embodiment.

FIG. 2 is a schematic view of all of the apparatus for setting blindrivets, according to an electrohydraulic embodiment.

FIGS. 3 and 4 are circuit diagrams for the control of the power circuit.

FIG. 3 is a power circuit diagram.

FIG. 4 is a control circuit diagram.

FIG. 5 is a schematic view of the apparatus for positioning nuts to beset.

FIGS. 6 and 7 show a particular embodiment of the motor mounting.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The apparatus according to the invention for positioning nuts to be setor for setting blind rivets, is of the type comprising anelectroportable body 1 containing an electric motor 2, a mandrel 3,drive means to hold and pull the head of rivets and/or to pull, screw orunscrew the nut to be set.

According to the invention, the electric motor is a motor couple 2.

The amplitude of the path of the mandrel 3 is pre-adjustable as afunction of the size of the nut or rivet to be set.

According to the embodiment shown in FIG. 1, in which the apparatus is amechanical apparatus for setting blind rivets, the motor-couple 2 drivesa ball screw 3, which is disposed in a ball socket 4, which drives a setof levers 5, said levers being connected to a toothed wheel 6.

According to a modification, this ball socket can be mounted on anoscillating roller structure so as to have all the elements in line.This embodiment is not shown in the figures.

In another embodiment, shown in FIGS. 6 and 7, the motor assembly 2 ismounted so as to permit freedom of pivoting relative to theelectroportable body 1. This freedom of movement is integrated into thekinematics of mounting and descent of the ball socket 4. This design isvery effective and less costly for production.

Thus, the motor 2 can be pivotally mounted by the bias of a fork 19without other necessary articulations.

This toothed wheel 6 engages a rack 7 which is an integral part of thebody of mandrel 3. The mandrel 3 is a hollow mandrel, which permitsrecovering the heads of the rivets in the recess 8 provided for thispurpose along the axis of the end 9 of the hollow mandrel 3.

The hollow mandrel 3 is facilitated in its movement by a sliding pad 10disposed about the head 11, which holds the mechanism together.

The end 12 of the hollow mandrel 3 comprises a jaw-carrying cone 43, thejaws are not shown, nor the pusher and the spring. The nose 14 securedto the head 11 carries the traction broach 15. The assembly of themechanism is maintained by a frame 16. On this frame 16 is disposed aslide 17. The pre-selection of the rivet and/or the nut to be set iscarried out manually by the slide 17, which moves a movable detectorrelative to a fixed detector. The fixed and movable detectors are notshown in the drawings.

According to another embodiment, the pre-selection of the nut and/or therivet to be set is carried out by a potentiometer which electronicallycontrols the course of the mandrel 3.

The trigger 18 actuates the motor-couple 2.

FIG. 2 shows an electroportable apparatus for positioning and settingblind rivets whose shank ruptures, in an electrohydraulic version shownin FIG. 2.

In FIG. 2, there is seen an actuating trigger 20, a motor-couple 21,which actuates the pump 22. The trigger is connected to a distributorconnected to a connection ferrule 24, itself connected to anotherferrule 25, which is connected to the hydraulic circuit 26 and 27, whichsupplies a point A and a point B, on opposite sides of the piston 28,secured to the hollow mandrel 29. O-rings are shown and ensure thesealing of the hydraulic assembly. A return spring 30 ensures return ofthe hollow mandrel 29. The end 31 of the hollow mandrel is disposed atthe level of the recess 32, which collects nails when they are pulled.

The end 33 of the hollow mandrel is located at the level of the nose 34and of the pulling broach 35, of the electrohydraulic riveter.

The trigger 20 has two functions:

first, the trigger 20 closes in the first instance the hydraulic circuitA and B.

secondly, the same trigger starts the motor-couple 21, which drives thepump 22, for the regulated pre-established path.

Release of the trigger 20, by opening the hydraulic circuit, drives thereturn of the piston, namely of the hollow mandrel rearwardly.

FIG. 3 shows the power circuit in the case of the electromechanicalapparatus, and FIG. 4 shows the control circuit.

The motor is applied by the power circuit represented in FIG. 3 closedby the relays OSP1, OSP2 which permit the flow of current and itsinversion. The control circuit shown in FIG. 4 is controlled by asequential command OS4 or a maintained contact OS5. This control isembodied in the trigger 20 or 18 for control of the machine. The currentthen flows through the first branch of the control circuit, the relayOSP1 is closed, but the relay OSP2 is open, the direction flow isdirect.

This branch is opened by the contact OS3, which symbolizes the end ofpath contact. The switch OS6 swings then to supply the branch 2 of thecontrol circuit which adjusts the relay OSP1 open and the relay OSP2closed. The power then flows in the opposite direction. The motor Mchanges its direction of rotation and returns the assembly of the mobiledevice to its initial position. If it is desired to interrupt theoperation in the middle, a second pull on the trigger returns theapparatus to the zero position.

The embodiment shown in FIG. 5 is an electroportable apparatus forpositioning nuts to be set. In this embodiment, there are seen all theelements already described in the different figures, if it is only themandrel 36 that is imperforate, because there is no recovery of theheads of the rivets, but at the level of the nose 37, the ferrule 38 isscrew-threaded to permit the emplacement of the nuts, and finally, atthe end 39 of the mandrel 36, is disclosed an electric motor 41 whichscrews and unscrews, thereby permitting the screw-threaded ferrule toscrew or unscrew exactly the nut to be set. The actuation is triggeredby the trigger 42.

Of course, a cursor 40 permits regulating exactly the path of themandrel, which path must be very precise so as not to break the threadof the nut to be set.

No matter what the form of the pre-adjustment means of the path of themandrel 3, 36, there is carried out an optimized path according to thesize of the rivet or of the nut, to ensure good securement withoutbreaking but also so as not to generate an overconsumption of electricalenergy by prolonging the path beyond what is necessary.

The pre-adjustment means from the form of the cursor 40 or 17 coact withdetectors of which one is movable, permitting these advantages.

Reference

1. electroportable body

2. electric motor

3. mandrel

4. ball socket

5. set of levers

6. toothed wheel

7. rack

8. recess

9. end of hollow mandrel 3

10. slide pad

11. head

12. end of hollow mandrel 3

13. ball screw

14. nose

15. pulling broach

16. frame

17. cursor

18. trigger

19. fork

20. actuating trigger

21. motor

22. pump

23. distributor

24. connecting ferrule

25. ferrule

26-27. hydraulic circuit

28. piston

29. hollow mandrel

30. return spring

31. end of hollow mandrel

32. recess

33. end of hollow mandrel

34. nose

35. pulling broach

36. mandrel

37. nose

38. ferrule

39. end of mandrel

40. cursor

41. electric motor for screwing and unscrewing

42. trigger

43. jaw-carrying cone

What is claimed is:
 1. Apparatus for positioning nuts to be set and forsetting blind rivets, comprising: an electroportable body (1) containingan electric motor (2), a mandrel (3), drive means to i) maintain and topull a head of the rivet and ii) to pull, screw and unscrew a nut to beset, means for pre-adjusting a path of the mandrel (3, 29, 36)permitting, after a pre-regulated course of the mandrel (3, 29, 36), anautomatic return, and an electronic control means to automatically makean adjustment of a path for a rivet whose dimensions have been selected,wherein, the electric motor drives a ball screw (13) connected vialevers (5) to a toothed wheel (6) actuating a rack (7) driving ariveting mechanism.
 2. Apparatus according to claim 1, characterized bythe fact that the adjustment of the path of the mandrel (3, 29, 36) is adistance adjustment.
 3. Apparatus according to claim 2, characterized bythe fact that the pre-adjustment means are constituted by a cursor (17,40) which moves a movable detector relative to a fixed detector. 4.Apparatus according to claim 1, characterized by the fact that thepre-selection of the rivet and/or of the nut to be set is carried out bya potentiometer which electrically controls the distance of the path ofthe mandrel.
 5. Apparatus according to claim 1, characterized by thefact that the electric motor (2) is a motor couple.
 6. Apparatusaccording to claim 1, characterized by the fact that the drive meansactuating the riveting mechanism are actuated by a hydraulicmicrocenter, the motor (21) actuates the hydraulic microcenter, and thetransmission of energy takes place by means of a hydraulic pump (22)which is an integral part of the hydraulic microcenter.
 7. Apparatusaccording to claim 1, characterized by the fact that the mandrel (3, 29,36) is adapted to position the nut and an electric motor (41) isdisposed along the working axis of the mandrel to screw or unscrew. 8.Apparatus according to claim 7, characterized by the fact that a trigger(42) of the apparatus is the control means, a first pull actuatesscrewing and a second pull actuates traction over a predetermined coursewith automatic return and a release of the trigger (42), an automaticunscrewing action for x turns of the motor and stopping the motor. 9.Apparatus according to claim 7, characterized by the fact that a triggeris connected to a distributor (23) connected to a connecting ferrule(24), itself connected to another ferrule (25), which is connected tothe hydraulic circuit (26) and (27), which supplies a point A and apoint B, on opposite sides of the piston (28), secured to the hollowmandrel (29), O-rings ensuring sealing of the hydraulic assembly, areturn spring for the hollow mandrel (29), the end 31 of the hollowmandrel is disposed at the level of the recess (32), which collectsitems that are pulled, and that the end (33) of the hollow mandrel islocated at a level of the nose (34) and of a pulling broach (35). 10.Apparatus according to claim 9, characterized by the fact that thetrigger (20) has two functions: first, the trigger (20) closes in thefirst instance the hydraulic circuit A and B, secondly, the same triggerstarts the motor (21), which drives a pump (22), for the preliminarilyadjusted path, and that the release of the trigger (20) by opening thehydraulic circuit, gives rise to the return of the piston, of the hollowmandrel, rearwardly.
 11. Apparatus according to claim 1, characterizedby the fact that the electric motor (2) is positioned substantiallyalong a vertical axis of the electroportable body (1) and is mountedwith freedom of pivotal movement relative to the electroportable body(1).